 in the Southern Carpathian Mountains, captured about 20 of the shower's bright streaks. )
A mountaintop above the clouds and light-polluted cities of Romania served as a good spot from which astrophotographer Alex Tudorica could watch the 2008 Perseid meteor shower. This composite picture from one of the highest points in Romania, the Omu summit (2,507 meters) in the Southern Carpathian Mountains, captured about 20 of the shower's bright streaks.
Image: Alex Tudorica/Argelander Institute for Astronomy
With the return of the brilliant planet Venus to our evening sky, I'm reminded of an amusing anecdote related by a good friend of mine, George Lovi, a well-known astronomy lecturer and author who passed away in 1993.
One night, while running a public night at the Brooklyn College Observatory in New York, the telescope was pointed right at Venus, which was displaying a delicate crescent shape at the time. Yet, one student gazing through the telescope eyepiece stubbornly insisted that he was really looking at the moon. When George pointed out that the moon wasn't even in the sky, the student replied, "So what? Doesn't a telescope show you things you can't see without it?"
That story got me thinking about a number of popular misconceptions in astronomy. Here's my own personal list of ten, in no particular order:
1. Why don't most meteor showers "shower?"
When an announcement is made through the news media about an upcoming meteor shower, it likely will conjure up visions in the minds of many of a sky filled with meteors pouring out of the sky like water from a hose.
Unfortunately, in just about all cases, your average meteor shower is a far cry from that. Typically, if you're outside on a clear, dark night you might catch a glimpse of perhaps three to six meteors (popularly called "shooting stars") over the course of an hour's watch.
On certain nights, the hourly rate may be somewhat higher, in which case astronomers would say that a "meteor shower" is in progress. In the middle of August or the middle of December for instance, you might notice that meteors are comparatively plentiful; perhaps coming at a rate of about one per minute. Indeed, these are the times of the two best meteor displays of the year, although it would never occur to you that a "shower" was in progress. [2011 Orionid Meteor Shower Photos]
There are rare occasions, when Earth interacts with a dense trail of dust recently shed by a passing comet, and meteors will seem to literally pour from the sky in a shower-like fashion. Unfortunately, such opportunities are few and far between. On May 31, 2022 however, we just might get a chance to witness a true "storm" of meteors, with potential rates of thousands per hour. On that night, Earth might pass through the dusty debris that was shed by a comet that broke apart into several fragments in 1995.
2. Can artificial satellites really be seen with the unaided eye?
Most definitely! In fact, many people are surprised that an object orbiting hundreds of miles above our heads can be readily seen without the use of binoculars or a telescope. From the launch of the first satellite, Sputnik, in 1957 to the present, the number of satellites in space has grown at a spectacular rate. There are now over 10,000 satellites orbiting the Earth.
British astronomer Desmond King-Hele once noted that a satellite, "looks like a star that has taken leave of its senses and decided to move off to another part of the sky."
If you go out and carefully study the sky near dusk or dawn, the odds are that you should not have to wait more than 15 minutes before you see a satellite now in orbit. Most are too faint to be seen with the unaided eye, but a few hundred are large enough and low enough (100 to 400 miles/160 to 640 kilometers above Earth) to be seen. [Photos: Spotting Satellites & Spaceships from Earth]
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8 Comments
Add Comment7. "Must I wait almost 400 years to see a total eclipse of the sun?"
Reply | Report Abuse | Link to this"Not unless you don't mind doing some traveling." Actually the opposite is true. If you DO mind doing some traveling, then you must wait.
Seeing satellites can be done every clear night; but watch out! when they pass in to Earth's umbra they lose solar illumination and disappear before your very eyes.
Reply | Report Abuse | Link to this"Not unless you don't mind" is in effect a double negative, so it is correct.
Reply | Report Abuse | Link to thisRead it again. I am not going to spend my time explaining it.
Reply | Report Abuse | Link to thisHere is one I think I've figured it, but I've never seen verified. -- what are your thoughts.
Reply | Report Abuse | Link to thisThere is really no such thing as a full moon. In order for a moon to be full it needs to be directly opposite the Earthmfrom the Sun, which makes it an eclipse. The monthly full,moon might better be called a "fullest" moon because it is the closest the moon will get to full,for that month. Of course the total deviation from being truly fully lit may be small, and because of scatter and bending there may be some illumination over the entire surface. This is why I'm not fully sure that a full moon isn't full. Any comments?
This article gives me a chance to ask two more of my idiot questions, that I've long wondered about.
Reply | Report Abuse | Link to thisThe lesser one is, why are solar eclipses so frequent? Is the fact that the moon's orbit intersects the axis between the sun and the earth a coincidence? Or is there a gravitational reason why they tend to align?
If my first question is about the seeming unlikeliness of the earth, moon and sun aligning, then the second question, which has really bothered me for a long time, is that it is even more unlikely that the moon's orbit will be (near enough) EXACTLY at such a distance as to produce a total eclipse! Is it a coincidence that it's not further away to be half the perceived size of the sun, or so close to be seen as twice as large? Even if there is a gravitational reason, isn't it still a coincidence that the moon's density (and therefore it's size) happens to be what it is?
Reply | Report Abuse | Link to this4. Is it hot in July because we're closest to the sun?
No! In fact, the Earth is at its farthest point from the sun in early July, and is closest to the sun in early January. The difference in distance from the Earth to the sun between these two extremes is about 3 million miles (5 million km), or 3.3 percent, which makes a difference in radiant heat received by the Earth of nearly 7 percent. [Top 10 Surprising Results of Global Warming]
Thus for the Northern Hemisphere, one would assume that this difference tends to warm the winter and cool the summer. Instead, the large landmasses in the Northern Hemisphere actually work the other way and tend to make the winters colder and summers hotter than those of the Southern Hemisphere.
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Really?
And what effect does the more tangential exposure to the more southern sun have in the northern winter?
(hint: the axis of the Earth's rotation is tilted 23+ degrees to its orbital plane.)
Looks as if the editor took a day off.
Bob
WRT "In contrast, at full moon, the sun is shining straight down virtually everywhere on the lunar surface (except near its edges) so that there are no shadows at all. "
Reply | Report Abuse | Link to thisYes, we understand the near parallelism of the rays of sunlight, but a rock 25 % of the way from one edge of the full disk to the other (for example) will, of course, cast a shadow.
(hint: Stand in the center of what appears to us to be the full moon. Where is the sun? [overhead] Now walk to the edge of the illuminated disk. Where is the sun? [It's not overhead any more.]
When is the editor getting back from vacation?